I think it may help to realize that chances are, these forms were designed with physical disabilities in mind. If you think back, it was physical disabilities that would get people off of work.....

I say this as someone who had a hard time filling out those darn forms, too. (For SSDI they do send some directly to the patient to fill out.) It was maddening b/c it felt like my disability didn't fit into any of those stupid blanks! But, in the end, my anxiety does prevent me from being able to hold down a job because of the extremely unpredictable nature of it all. Its just a matter of figuring out the right way to say it all so that they understand your symptoms and why your symptoms prevent you from being able to work or hold down a job.